1. Technical Field
The invention relates generally to the field of roof coverings. Specifically, the invention relates to a modular system for providing storm water management and roof-protective vegetation on roof tops.
2. Description of the Related Art
The type of roof covering that is used on a building or dwelling can have a dramatic impact on the living conditions inside. As an example, roof coverings that provide significant solar energy collection can reduce the amount of heat energy transmitted into the living area of a building, which can lead to reduced energy costs (costs associated with cooling the living area) during hot periods. One type of roof covering that has received significant interest recently is a so-called ‘green roof’ system. Green roof systems typically incorporate some type of vegetation in a roof covering. Green roof systems can lead to reduced energy costs, due to the insulating effects of the vegetation, reduced storm-water runoff, due to the water-absorbing nature of the vegetation and accompanying soil, and environmental advantages, due to increased green space in commercial or other populated areas.
One prior art roof covering is disclosed in U.S. Pat. No. 6,606,823 to McDonough et al (hereinafter “McDonough”). McDonough provides a roof covering system consisting of modular trays that may be used to hold vegetation, absorbent material, or solar cells. The trays in McDonough require several layers of different materials as well as some type of ballast to weigh down the trays. Further, the McDonough trays have a complicated and expensive puzzle-type interlocking frame which leaves a gap between adjacent trays. These gaps represent un-captured roof area that does not realize the benefits of the green roof system. Also, the gaps between the trays allow soil mixture to spill out of the trays and onto the frame between the trays. This spilled soil mixture can lead to water pooling underneath the roofing system and subsequent damage to the roof below the roofing system. Consequently, a roofing system that does not have gaps between adjacent trays and does not require many layers of materials is desired.
Another prior art system is disclosed in U.S. Pat. No. 6,862,842 to Mischo (hereinafter “Mischo”). Mischo provides a modular green roof system that consists of pre-seeded panels that have edge flanges for connection purposes. The flanges of adjacent trays laterally abut or rest on top of each other and must be screwed or bolted together in order to secure the adjacent trays. The edge flanges space the trays apart. These screw or bolt type connections can add significant time and expense to the installation of the Mischo system. Consequently, a roofing system that does not require screwed or bolted connections between adjacent trays is also desired. It is also desired to maximize coverage of the roof by the trays.
The invention addresses these and other disadvantages of conventional roofing systems.